i run a magnaflow with 2 1/2 in inlet and oulet and 2 1/2 in tailpipe and it sounds really good and I did see a little better performance. I would recommend instead of buying some high dollar kit find a good muffler shop and choose your muffler and have them bent the pipe. You'll be money ahead in the long run.
Harvenger [img]/wwwthreads_images/icons/laugh.gif[/img] 93 Nissan Xcab 4wd V-6 161,000 miles
93 Pathfinder 4wd V-6 70,000 miles